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Field Measurement of Running Impacts

Final Design Report

May 9, 2007

Team Members: Chelsea Wanta, Amanda Feest, Matt Kudek, Lindsey Carlson, Nicole Daehn

Client: Dr. Bryan Heiderscheit, PhD, PT

Advisor: Paul Thompson

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Table of Contents:

Abstract……………………………………………………………………………………3

Design Problem…………………………………………………………………………....3

Background Information….……………………………………………………………….3

Client Motivation………………………………………………………………………….4

Design Constraints…………………………………………………………………….......6

Preliminary Designs……………………………………………………………………….7

Hardware Design Matrix…………………………………………………………………10

Accelerometer Attachment Design Matrix………………………………………………12

Data Logger Attachment Design Matrix…………………………………........................13

Final Design………………………………………………………...................................13

Data Acquisition and Analysis…………………………………………………………...14

Conclusion……………………………………………………………………………….20

References……………..……………..……………..……………..……………..………21

Appendix One – Product Design Specification...……………….……………………….22

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Abstract:

Dr. Bryan Heiderscheit is a physical therapist whose goal is to identify

characteristics of running that lead to stress fractures. The purpose of this project is to

create a portable system that records tibial acceleration data to measure the impacts of

running. This device will include a lightweight accelerometer which will record data to a

data logger. The acceleration data will be used to assess and treat running-related

concerns. Three designs alternatives have been considered: a wired system, a wireless

system, and a microcomputer. These designs were evaluated using a design matrix,

which compared certain design criteria set forth by the client. The best design, the wired

system, has been selected and a prototype of this design will be pursued. Future work

entails purchasing a data logger and accelerometer, constructing the device, and testing

the device to assure accurate data collection.

Design Problem:

The purpose of this project was to create a portable system that records tibial

acceleration data to measure the impacts of running. This device includes a lightweight

accelerometer which records data to a data logger. The acceleration data will be used to

assess and diagnose running-related injuries. The device also required an attachment

system to ensure the components are secured to the runner. Finally, a testing system was

designed to verify the data from the accelerometer.

Background Information:

Stress fractures are one of the most common running injuries. Around fifty

percent of all runners suffer from a stress fracture at some point during their running

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career (Milner). Tibial stress fractures are very painful and can hinder activity for a

period of three to six weeks. Between 33 and 55 percent of all stress fractures occur in

the tibia, which is the inner of the two bones in the lower leg (Milner). In adults, these

fractures usually occur in the anterior junction of the lower third of the bone, as shown in

Figure 1. They occur when muscles become fatigued and are unable to absorb added

shock. Eventually, the fatigued muscle transfers the overload of stress to the bone, which

is thought to cause stress fractures (American Academy of Orthopedic Surgeons). In

order to prevent stress fractures, it is very important to learn about the possible causes

and to find a way to prevent them from occurring.

Figure 1: Anatomy of a typical stress fracture (Smith).

Client Motivation:

Our client, Dr. Heiderscheit, is a physical therapist who operates the UW Health

Runners’ Clinic. One of the goals of his clinic is to identify characteristics of running

that lead to stress fractures. Dr. Heiderscheit wants to use acceleration data to measure

the peak impacts absorbed by the bone. With this data, he hopes to adjust his patients’

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running style in order to reduce their risk of stress fractures and other running-related

injuries.

Dr. Heiderscheit currently has both a clinical and a research set-up in his lab. In

his clinical setting, patients run on a treadmill while their lower body is videotaped

(Figure 2). Feedback is then given to the patient based on a visual analysis of their

running form. In the research set-up, markers and accelerometers are attached to the

subject while he or she runs on a treadmill. Acceleration data is recorded and graphed on

a computer, allowing for quantitative analysis of the impacts. Dr. Heiderscheit hopes to

incorporate a quantitative analysis into the clinical studies.

Figure 2: Client’s current clinical set-up

Our design would incorporate the benefits from both set-ups while minimizing the

disadvantages. The design would retain the simplicity of the clinical set-up while still

allowing Dr. Heiderscheit to collect statistics about the impacts similar to his research

studies. Currently, research subjects are hooked up to extensive wiring, a process which

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can take over an hour. Since the client only sees clinical patients for a half hour, this

method of collecting data would not be feasible in the clinical setting; however, our

design could be attached to the runner in a matter of minutes. Also, both current methods

prevent patients from running in their ‘natural’ environment. For this reason, our client

wants to create a portable device that can measure tibial accelerations on various surfaces.

Runners will use the device when they run on their normal running path. After going for

a run, the data can be brought back to the lab for analysis. This type of device is

necessary for our client to quantitatively diagnose a patient as being susceptible to stress

fractures.

Design Constraints:

The most important aspect of our final design is to create a portable and user-

friendly data logging system that reliably measures tibial accelerations. This device must

consist of a data logger, accelerometer, and system to attach the device to the body.

Since this system is used for running, the accelerometer and data logger must be

lightweight and not interfere with the runner’s gait. The uniaxial accelerometer must be

able to read up to 25G peak acceleration. The data logger should be able to collect data

at 1000-2000 Hz to make sure all peak accelerations are accurately detected. This system

should also be able to store data for at least ten minutes and should have several inputs to

allow for multiple accelerometers in the future. Lastly, this system should be completed

for use in studies during the summer of 2007. For a complete list of design

specifications refer to the PDS in Appendix 1.

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Preliminary Designs:

Three alternative designs were developed to meet the design criteria. The first

design was a wired device which included an accelerometer connected to a data logger

via a wire running up the leg. The data logger would be worn on a belt around the

runner’s waist. The accelerometer would be attached to the leg a few inches above the

ankle joint on the tibia. The wire connecting the two components would be taped to the

outside of the runner’s leg as to not impede the runner’s performance. Power for the

accelerometer would be supplied by the data logger. The data logger would have an

output that would allow for the data to be easily transferred from the data logger to a

computer. See Figure 3 for the first design alternative.

Figure 3 : Data logger (MIE Medical Research Ltd.) (left), accelerometer (PCB Piezotronics) (right) The second design alternative was a wireless device which used Bluetooth

technology to communicate between the data logger and accelerometer. Like the previous

design, the data logger would be worn on a belt and the accelerometer would be securely

attached to the leg. This design did not require a wiring system between the components;

however, additional equipment would be needed to make this communication possible.

An RS-232 converter would be necessary to equip the data logger with technology to

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receive Bluetooth inputs. Since the accelerometer would not be attached to the data

logger, it would also need its own power supply. See Figure 4 for the second design

alternative.

Figure 4: Wireless accelerometer (Spark Fun Electronics) (left). RS-232 Converter (Tek Gear ) (right). The final design alternative was a device which would be worn entirely on the leg

and included an accelerometer, amplifier, analog-to-digital converter, and a

microcomputer. All these components would be integrated onto a circuit board. The

acceleration data would be sent through the amplifier to an analog-to-digital converter,

and then stored to a memory chip. The microcomputer would be used to analyze and

store data from the accelerometer which would later be downloaded to a computer. Only

one power source would be need for this entire system. See Figure 5 for the third design

alternative.

Figure 5: Schematic of the microcomputer device.

Another important component to the final design was creating an attachment

system for the data logger and accelerometer. The data logger needed to be worn

securely on the runner’s waist. Two alternatives were considered to fasten the data

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logger to the runner: a clip-on pouch and a waist belt. The clip-on pouch would consist

of a fabric holder and a clip attached to the back. The data logger would be fastened into

the pouch and then clipped onto the runner’s shorts. The other option would be a belt to

hold the data logger. The inspiration for this design came from an iPod belt designed for

running. This belt would be adjustable for most waist sizes and would securely hold the

data logger. These two options are shown in Figure 6.

Figure 6: Clip-on holder (PC Tronix) (left). Belt holder (Proporta) (right).

In order to ensure that data was gathered accurately, the accelerometer must not

move relative to the tibia, so a device must be designed to secure it. Two options were

considered: a leg sleeve and an elastic band. The sleeve would be made out of a stretchy

material, such as spandex, and would be slipped over the leg. The sleeve must be tight to

the leg, but not restrict the runner’s blood flow in any way. The other option would

include an elastic band with Velcro attached to it. This would allow it to be adjusted to

any leg size and would also control how tight the band was on the leg. See Figure 7 for

accelerometer attachment options.

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Figure 7: Leg sleeve (Germes) (left). Elastic band (right).

Hardware Design Matrix:

Wired Wireless Microcomputer Signal Reliability (40) 10 7 10 Feasibility (30) 10 6 3 Lightweight on leg (20) 9 7 6 Comfort (10) 6 7 8 Total (100) 94 61 69

The best design was selected based on a weighted design matrix using four main

criteria (See Figure 8). The most important (and therefore highest weighted) criterion is

signal reliability, since the device is useless if it cannot receive the signal from the

accelerometer. A hardwire connection would provide the most reliable signal. The wired

design and the microcomputer device received a ten because the accelerometer and the

data logger are directly connected. The wireless design received a seven because it

involves signal transmission via Bluetooth, which introduces the possibility of

interference from other electronic devices.

We also evaluated the feasibility of completing the project within the client’s

desired time frame. It is important to have a functional prototype by the end of the

semester because our client plans on using this device this summer, so this category was

Figure 8: Hardware Design Matrix.

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weighted second highest. The wired system received a ten because we could buy all of

the parts. The wireless design received a seven in this category based on the fact that we

cannot find a data logger with wireless inputs. The microcomputer design was the least

feasible, receiving a three, because we did not believe it would be possible to design a

microcomputer in one semester since none of our members have advanced knowledge of

circuits.

The third consideration in the design matrix focused on how much weight would

be added to the leg. It is important to minimize the weight worn on the tibia since

excessive mass would alter the stride of the runner and result in data inconsistent with the

runner’s normal stride. The wired design was the most lightweight because only the

accelerometer is worn on the leg, and therefore received a nine. The wireless design

scored a seven because an additional power supply must be attached to the leg. Finally,

the microcomputer device received a six because all components are worn on the leg.

The final category we judged was the comfort of the device. The wired design

received a six since the data logger must be worn on the waist with wires running down

the leg to the accelerometer. However, we believe that by securing the wires to the

runner’s leg, the wires can be prevented from snagging and this factor can be minimized.

The wireless design received a seven because it did not have the same problem with

wires, but still required a data logger to be worn on the waist. The microcomputer

received the highest score in this category because the device is relatively lightweight and

everything is worn on the leg, so it requires no wires. However, since there is added

weight to the tibia, it only received an eight in this category.

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Accelerometer Attachment Design Matrix:

Criteria (Weight) Spandex Sleeve Elastic Band Adjustability (70) 5 8 Comfort (20) 9 8 Ease of use (10) 8 10 Total (100) 61 82

We compared two options when selecting a method to attach the accelerometer to

the tibia: a spandex sleeve and an elastic band (See Figure 9). The most important

criterion in this choice was adjustability. A size-adjustable design provides a secure

attachment while still allowing normal blood flow. A secure attachment is essential for

accurate data since slight movements of the accelerometer relative to the tibia can result

in incorrect measurements. The spandex sleeve only received a four in the adjustability

category because although spandex stretches, that design option did not include any

method to account for runners with smaller legs. The elastic band solves this problem

because it allows the runner to resize the band to fit his or her leg, and therefore received

a nine in this category.

The other two categories are considerably less important, although they are worth

taking into account. The comfort of the device is important since the runner must be

comfortable while running to maintain their normal stride. While both designs would be

sufficiently comfortable, the elastic band received an eight because it would be

comfortable and allow air flow to the majority of the leg. However, this design would

involve Velcro® or stiff elastic, both of which could cause mild discomfort. The spandex

sleeve received a nine because it does not have any irritating materials. Finally, ease of

use was considered but weighted the lowest since it would only enhance the quality of the

design. The elastic band was considered very user-friendly because it can be fastened

Figure 9: Accelerometer Attachment Design Matrix.

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and removed without the runner removing his or her shoes. The spandex sleeve, on the

other hand, requires the runner to put the sleeve and accelerometer on before putting on

his or her shoes.

Data Logger Attachment Design Matrix:

Clip-on Belt Secure attachment (60) 6 9 Adjustability (30) 10 8 Ease of use (10) 10 10 Total (100) 76 88

Two major designs were considered to attach the data logger to the waist: a clip-

on unit and a belt (See Figure 10). The reliability of the attachment is extremely

important in the decision because the data logger is an expensive instrument, so the

design must prevent it from detaching from the runner. The belt is considered very

secure since it is fitted to the runner’s waist. The clip-on design is less secure because

running could cause the clip to move around on the runner’s shorts and possibly fall off.

In terms of adjustability, the clip-on device is the most adjustable because it can be

placed anywhere on the waist depending on the runner’s preference. The belt design is

less adjustable because the size of the belt is limited, but should fit most body sizes.

Finally, both designs would be easy to use because the data logger would simply clip in

place immediately before the run and would not require any other adjustments.

Final Design:

The final project design chosen has four components. These include a data logger,

an accelerometer, a belt to hold the data logger when being used, and a Velcro strap that

will be worn around the leg to secure the accelerometer while it is being used. The data

logger that was chosen for the system is from Medical Research Limited. This device was

Figure 10: Data Logger Attachment Design Matrix.

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strongly preferred by the client. Some features include: eight input channels, a 4000Hz

sampling rate, and a mass of 10 grams. Its dimensions are 72mm x 55 mm x 18mm. The

data logger also came packaged with a +/- 25G uniaxial accelerometer.

The belt that was chosen for the data logger is the “Proporta Tune Belt.” This belt

is a neoprene waist belt designed to secure an iPod for someone while running. Since this

belt is intended to be used while running, this was one of the primary reasons that this

belt was chosen for the project. Because it is expected to normally handle running

conditions, it was a good choice to protect an expensive component of the system.

Another reason that an iPod belt was selected for this project is that the dimensions of the

iPod and data logger are very similar. The belt has a pocket dimension of 4” x 2.75”

x .625” (157mm x 108mm x 24mm). The additional height of the pocket allows the

accelerometer “Y-connectors” to fit in the pocket without being damaged.

The Velcro® leg band design was made from an elastic band. The band is three

inches wide and twelve inches long, which should be long enough to fit around an ankle

of most runners. There are four strips of Velcro® attached to the band in order to secure

it. By having separate sections of Velcro® instead of one long strip, the band can still

stretch in places, making it more flexible and adjustable. A metal loop was attached to

one end of the band so that the Velcro® can be fed through so that the Velcro® will

attach properly.

Data Acquisition and Analysis:

To assess the quality of the data measured by the system, a testing device was

designed (see Figure 11). The testing apparatus consists of a wooden dowel supported by

a polypropylene board, a PVC pipe, and a piece of wood to ensure vertical movement. A

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spring was placed between the board and the bottom of the dowel to increase the

downward acceleration of the dowel. The accelerometer was attached to the top of the

dowel and the accelerations of the dowel were recorded. As the dowel was pulled up, the

spring compressed so that when it was released, higher accelerations were achieved due

to the decompression of the spring as well as gravity. A force plate in the client’s lab was

used as a reference point during testing since it was previously calibrated.

Prior to testing, the predicted plots for acceleration vs. time and force vs. time

were prepared (Taylor). These graphs helped to identify key points when obtaining

measurements from the testing device. On the force vs. time graph, there should be a

sharp peak corresponding to the initial impact of the dowel on the force plate and other

smaller peaks due to the forces of each bounce of the apparatus. Finally, the graph

Figure 11: Tester sitting on the client’s force plate

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should level out to an equilibrium value due to the weight of the dowel resting on the

force plate. (See Figure 12).

Figure 12: Predicted Force vs. Time

After the dowel was dropped, the acceleration vs. time graph would have an

initial acceleration from the force of the spring as well as gravity (Taylor). Once the

spring was no longer compressed, the dowel should accelerate solely due to gravity. As

the dowel hit the force plate, it should decelerate sharply, creating a sharp decline in the

graph. (See Figure 13).

Figure 13: Predicted Acceleration vs. Time

Acceleration vs. Time U

pw

ard

Acceleratio

n

Do

wn

ward

A

cceleration

Time Time interval when tester

hits force plate

Acc. due to gravity and

spring

Acc. due to gravity Oscillations due to

elasticity of collision

Force vs. Time

Time

Fo

rce

Time interval when tester hits force plate

Equilibrium between force

plate and device

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The impulse could be calculated based on the values of the integrals over the time

interval that the dowel hits the force plate as shown in the following impulse-momentum

equation:

These impulse values could be compared to assess the accuracy of the accelerometer

against the reading from the force plate.

The data collected from testing was similar to the expected data. A height vs.

time graph was obtained using markers to measure the height of the dowel (See Figure

14). This graph was used to relate the data on the other graphs to the events that occurred

in testing. From this plot, the time of first impact was between 2.8-2.9 seconds. The

smaller peaks after 2.9 seconds correspond to the dowel bouncing on the force plate after

the initial impact. Near the end, the dowel rested on the force plate, corresponding to the

flat section from 3.5-5.0 seconds.

Figure 14: Height vs. Time Graph

A Force vs. Time graph was prepared from the data recorded on the force plate

(See Figure 15). The major peaks were the points of interest and the small peaks in

between were due to the vibrations of the force plate after impact. There is a general

Height vs. time (mm)

325

330

335

340

345

350

355

360

365

370

0 1 2 3 4 5 6

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exponential decay with each successive bounce, matching the predicted behavior due to

energy dissipating from the system. The initial peak corresponds to the time interval over

which the dowel hit the force plate. Furthermore, each point on the force graph

corresponds to a point on the acceleration graph.

Force vs. Time

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

2000

2500

2.8 2.9 3 3.1 3.2 3.3 3.4

Figure 15: Force vs. Time Graph

Using the data measured by the accelerometer, an Acceleration vs. Time graph

was generated (See Figure 16). The initial drop on the graph corresponds to the dowel

hitting the force plate. The small oscillations between each peak occur due to the

vibrations of the accelerometer. Each successive spike is due to the accelerometer

bouncing. Between each peak, the accelerometer decelerates for a longer time than

predicted because the collision between the force plate and the dowel is not perfectly

elastic. Each successive peak is smaller because the system loses energy. Eventually, the

acceleration will reach zero when the dowel is resting on the force plate. From this data

analysis, an accelerometer could be calibrated using these values as reference points.

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Acceleration vs. Time

-2500

-2000

-1500

-1000

-500

0

500

1000

1500

2000

2500

2.8 2.9 3 3.1 3.2 3.3 3.4

Figure 16: Acceleration vs. Time

To test the attachment system, a mock set-up was used since the hardware had not

arrived (see Figure 17). A rectangular block was used in place of an accelerometer and a

wire was run up the leg and secured using athletic tape. Marks were placed above and

below the leg strap before a run to detect any movement of the leg strap. After the runner

had run for five minutes, no movement or discomfort was reported. The wiring did not

interfere with the runner’s gait and it stayed firmly attached to the runner’s leg. The

overall system was reported to be very light-weight and ideal for running conditions.

Figure 17. Mock set-up of the leg attachment system.

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Conclusion:

Over the course of the semester, our group developed a comprehensive system for

measuring the accelerations of the tibia during running. Our design, the first prototype, is

a device that consists of a separate data logger and accelerometer. Wires run from the

data logger, which is worn on a belt, to the accelerometer, which is mounted on the lower

tibia. The accelerometer is attached using medical tape and an adjustable elastic band.

The accelerometer can easily be tested to verify the data using the testing device.

Several options could be pursued in future prototypes. One future goal would be

to reverse-engineer an accelerometer, modeling it after the ordered part. The testing

device could then be used to verify that the reverse-engineered accelerometer is accurate.

From there, there are two paths that could be pursued: designing a microcomputer or

developing wireless capabilities. A microcomputer design would eliminate the need for a

separate data logger since the accelerometer and data logger would be integrated into a

unit compact enough to be worn on the tibia. If the wireless route is pursued, there is a

possibility of using a device worn on the wrist to display the values from the

accelerometer to provide instant feedback.

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References

American Academy of Orthopedic Surgeons. “Stress Fractures.” May 6, 2007

<http://orthoinfo.aaos.org/fact/thr_report.cfm?thread_id=46>.

Germes. 2007. May 6, 2007. <http://germes-

online.com/direct/dbimage/50340788/Leg_Support.jpg>

MIE Medical Research Ltd. “Data Logger.” 2004 MIE Medical Research Ltd. Feb. 8,

2007. <http://www.mie-uk.com/datalogger/index.html>.

Milner et al. Biomechanical factors associated with tibial stress fractures in female

runners. Med Sci Sports Exerc 2006;38:323-328.

PCB Piezotronics. “Model 352A24.” 1999-2000. PCB Group, Inc. Feb. 16, 2007.

<http://www.pcb.com/searchresults.asp?searchcriteria=352a24>.

PC Tronix. 2007. May 6, 2007. <http:// www.pctronix.co.nz/images/APPB7815X.jpg>

Smith, Carrie Myers. “Stress Fractures.” Brigham and Women’s Hospital. 2005. Nucleus

Communications. Mar. 11, 2007. <http://healthgate.partners.org/browsing/browse

Content.asp? fileName=11532.xml&title=Stress%20Fracture>.

Spark Fun Electronics. “Wireless Accelerometer / Tilt Controller version 2.5.” 2005.

Spark Fun. Mar. 18, 2007. < http://www.sparkfun.com/commerce/product_info.

php?products_id=254>.

Taylor, Michael. Personal interview. April 24 2007, May 1, 2007.

Tek Gear. “Brainboxes BL-730.” 2007. TekGear.com. Feb. 21, 2007.

<http://www.tekgear.com/index.cfm?pageID=90&prodid=227&section=73&node

list=1,73&function=viewproducts>.

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Appendix 1

Running Impacts Product Design Specification (PDS)*

Amanda Feest, Chelsea Wanta, Matt Kudek, Lindsey Carlson, Nicole Daehn

5/9/07

Function: The completed prototype will measure the impacts of running using tibial acceleration data. The device should use accelerometers, which will record data to an incorporated data logger. The device must be easily worn by the user, and the hardware should have the ability to do most of the data processing. The design should include a system to attach the hardware to the runner’s body. This instrument will be used to diagnose stress fractures and other injuries related to running.

Client requirements (itemize what you have learned from the client about his / her needs):

• $1500 budget excluding data logger • Durability and battery life are important for field use • Continuous, solid, reliable signals are required • Ensure that accelerometer does not move with respect to the tibia • Data should be processed either by the data logger or software • Unilateral tibial acceleration measurements will suffice for the first prototype • System should be portable • Must have a system to securely attach the device to the runner • Accelerometer should be calibrated

Design requirements:

1. Physical and Operational Characteristics

a. Performance requirements: Ideally, the runner will take the device into the field and record data from three runs. The battery life and memory must be able to accommodate this criterion. The accelerometer must be secured tightly to the leg to prevent it from sliding on the leg while running, which could result in inaccurate data.

b. Safety: The equipment and wiring needs to be secured to the runner.

c. Accuracy and Reliability: Data logger should record data at a sampling rate of 1-2 kHz. The accelerometer should be able to record peaks of 25G’s, although it should have good resolution for the 0-20g range since

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this is the normal range. Additionally, a testing system should be developed to ensure that the data collected by the system is accurate.

d. Shelf Life: Device should be able to be powered off when not being used to save power.

e. Operating Environment: The device will be used primarily outdoors. Therefore, the device must be able to withstand variations in temperature and other weather elements like wind and humidity. The device would be exposed to considerable dirt and dust from the atmosphere. The device will be moving up and down with the runner, so all connections should be secure.

f. Ergonomics: Any device pieces that are worn on the leg should be placed on the outside or back of the leg to prevent damage due to running style. The wiring should not interfere with the runner’s strides. The individual components should be tightly secured to the runner’s body to prevent bouncing.

g. Size: Everything must be able to be worn while running.

h. Weight: The unit should be as lightweight as possible to maximize comfort. The portion of the device that is worn on the tibia must be especially light so that it does not interfere with the runner’s gait

i. Materials: The device must be attached to the runner’s tibia using a material that will conform to the leg’s shape either by wrapping or using a relatively elastic material.

2. Production Characteristics

a. Quantity: One.

b. Target Product Cost: The budget for the product is $1500, excluding the cost of the data logger.

3. Miscellaneous

a. User: The device should be comfortable to wear when running (for example, the device doesn’t bounce when running and the wires don’t snag easily).

b. Patient-related concerns: The device must be able to be wiped with a disinfectant between patients.

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c. Competition: Current set-ups are stationary, so the patient must come to the lab to partake in the study. The impacts cannot be measured over the runner’s normal paths. No portable devices can be found on the market.

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Field Measurement of Running Impacts Client: Bryan Heiderscheit, PhD, PT Team Members: Feest (co-leader) Wanta (co-leader) Kudek (communications) Daehn (BSAC) Carlson (BWIG) April 20 to April 26, 2007 Problem Statement Design an instrument that measures the impacts of running using tibial acceleration data. The device should combine the use of accelerometers and gyroscopes, which will record data to an incorporated data logger. The device must be easily worn by the user, and the hardware should have the ability to do most of the data processing. This instrument will be used to diagnose stress fractures and other injuries related to running. Last Week’s Goals

• Buy materials for the tester and build • Buy materials for the leg band and sew • Continue looking into waist attachment for data logger • Set up a time to calibrate accelerometer in the client’s lab

Summary of Accomplishments • Purchased materials for the tester and built the device • Made the leg band • Set up meeting on Friday to try out tester

This Week’s Goals • Calibrate the accelerometer using the tester we built • Create the poster • Split up sections of the paper

Project difficulties • Products are not coming in from the UK

Activities

• Went shopping for the supplies • Built the tester and leg band • Amanda-4 hours • Chelsea-4 hours • Matt-4 hours • Lindsey-4 hours • Nicole-4 hours

Expenses

• None to report so far

Jan. February March April May Task 26 2 9 16 23 2 9 16 23 30 6 13 20 27 4 11

Product Development

Background research

Develop design alternatives

Select final design

Order necessary equipment

Build Final Design

Test Prototype Presentations Midsemester Presentation

Final Presentation

Deliverables Progress Reports Midsemester Report

Final Report Meetings Advisor Client Website